Method of manufacturing a fastening system for an absorbent article

ABSTRACT

A fastening component for releasable engagement with a complementary fastener includes a substrate and a first fastener formed of a flexible fabric. An adhesive substance is disposed between and bonded to the first fastener and the substrate. The adhesive substance has a first zone with a first basis weight greater than zero, and a second zone with a second basis weight at least about 1.5 times greater than the first basis weight.

This is a divisional application of application U.S. Ser. No.08/366,077, filed on Dec. 28, 1994 now U.S. Pat. No. 5,476,702.

BACKGROUND OF THE INVENTION

The present invention relates to articles for absorbing body fluids.More particularly, the invention pertains to a fastening systemincluding a flexible fabric fastener for securing a disposable absorbentarticle about a wearer.

Disposable absorbent articles such as diapers, incontinenceundergarments, feminine products, or the like have heretofore included awide variety of fastening systems for securing the product about thewearer. For example, previous fastening systems have included tapefastening tabs, garment attachment adhesives, button and button holesystems, snaps, belts, and the like. Previous fastening systems havealso included hook-and-loop fasteners which provide several desirablecharacteristics, such as ease of adjustment for fit, and one-handapplication and removal.

Current fastening systems that employ a hook fastener that releasablyattaches to a loop fastener have several disadvantages as well. Forexample, the loop fastener is typically a flexible fabric having aplurality of loops formed on one major surface. The choices forattaching the loop fastener to the underlying substrate may be limited.Adhesives as used heretofore have tended to bleed through the porousfabric of the loop fastener and bond the loops to the base of the loopmaterial. This can significantly reduce the number of loops that areavailable for attachment to the hook fastener. The alternatives to usingadhesives to bond the loop fasteners to the substrate tend to employadditional components or equipment which tend to adversely impact highspeed manufacturing techniques.

Therefore, what is lacking and needed in the art is a fasteningcomponent that incorporates a fastener made of flexible fabric which issecurely held in place without deleteriously affecting performance.

SUMMARY OF THE INVENTION

In response to the discussed deficiencies in the prior art, a newfastening component has been developed. The fastening component providesenhanced resistance to failure resulting from shear forces withoutnecessitating additional components or equipment to bond the fastener tothe underlying substrate.

In one aspect, the present invention concerns a fastening componentincluding a substrate and a first fastener formed of a flexible fabric.An adhesive substance is disposed between and bonded to the firstfastener and the substrate. The adhesive substance has a first zone witha first basis weight greater than zero, and a second zone with a secondbasis weight at least about 1.5 times greater than the first basisweight.

In another aspect, the present invention concerns an absorbent articlehaving a first waist region, a second waist region, and a crotch regionpositioned between and interconnecting the first and second waistregions. The absorbent article includes a moisture barrier, an absorbentassembly disposed on the moisture barrier, and first and secondfasteners. The first fastener comprises a flexible fabric, and thesecond fastener is bonded to the moisture barrier in the second waistregion and adapted for releasable engagement with the first fastener. Anadhesive substance is disposed between and bonded to the first fastenerand the moisture barrier in the first waist region. The adhesivesubstance includes a first zone with a first basis weight greater thanzero, and a second zone with a second basis weight at least about 1.5times greater than the first basis weight.

In yet another aspect, the invention concerns a method of forming afastening component. The method includes the steps of: providing a firstfastener comprising a flexible fabric; providing a substrate; andapplying an adhesive substance between the first fastener and thesubstrate. The adhesive substance includes a first zone with a firstbasis weight greater than zero, and a second zone with a second basisweight at least about 1.5 times greater than the first basis weight.

The adhesive substance securely bonds the first fastener to theunderlying substrate. The amount of adhesive in the first zone isselected so that the adhesive does not bleed through to the surface ofthe first fastener that is adapted or engagement to a complementaryfastener. The amount of adhesive in the second zone, on the other hand,may be such that it penetrates the first fastener. The second zoneprovides a region of enhanced bonding between the first fastener and thesubstrate. The area and position of the second zone are desirablycontrolled so that the first fastener may thoroughly engage thecomplementary fastener.

Numerous features and advantages of the present invention will appearfrom the following description. In the description, reference is made tothe accompanying drawings which illustrate preferred embodiments of theinvention. Such embodiments do not represent the full scope of theinvention. Reference should therefore be made to the claims herein forinterpreting the full scope of the invention.

BRIEF DESCRIPTION ON OF THE DRAWINGS

FIG. 1 representatively shows a perspective view of a disposableabsorbent article according to the present invention.

FIG. 2 representatively, shows a plan view of portions of the disposableabsorbent article shown in FIG. 1, taken from the outer garment side ofthe absorbent article in a stretched and laid flat condition and withportions broken away for purposes of illustration.

FIG. 3 representatively shows an enlarged section view taken generallyfrom the plane of the line 3--3 in FIG. 2.

FIG. 4 representatively shows an enlarged section view taken generallyfrom the plane of the line 4--4 in FIG. 2.

FIG. 5 representatively shows an enlarged section view of an exemplaryloop material.

FIG. 6 representatively shows an apparatus useful in making fasteningcomponents for the absorbent article shown in FIG. 1.

FIG. 7 representatively shows a front view of a shim component of theapparatus shown in FIG. 6.

FIG. 8 representatively shows an enlarged section view similar to FIG. 4but illustrating an alternative embodiment of the invention.

DEFINITIONS

Within the context of this specification, each term or phrase below willinclude the following meaning or meanings:

(a) "bonded" refers to the Joining, adhering, connecting, attaching, orthe like, of two elements. Two elements will be considered to be bondedtogether when they are bonded directly to one another or indirectly toone another, such as when each is directly bonded to intermediateelements.

(b) "disposable" includes being disposed of after use and not intendedto be washed and reused.

(c) "disposed," "disposed on," "disposed with," "disposed at," "disposednear" and variations thereof are intended to mean that one element canbe integral with another element, or that one element can be a separatestructure bonded to or placed with or placed near another element.

(d) "elastic," "elasticized" and "elasticity" mean that property of amaterial by virtue of which it tends to recover its original size andshape after removal of a force causing a deformation.

(e) "elastomeric" refers to a material or composite which can beelongated by at least 25 percent of its relaxed length and which willrecover, upon release of the applied force, at least 10 percent of itselongation. It is generally preferred that the elastomeric material orcomposite be capable of being elongated by at least 100 percent, morepreferably by at least 300 percent, of its relaxed length and recover,upon release of an applied force, at least 50 percent of its elongation.

(f) "extension," "extend" and "extended" mean the change in length of amaterial due to stretching, expressed in units of length.

(g) "fabrics" is used to refer to all of the woven, knitted and nonwovenfibrous webs.

(h) "flexible" refers to materials which are compliant and which willreadily conform to the general shape and contours of the wearer's body.

(i) "force" includes a physical influence exerted by one body on anotherwhich produces acceleration of bodies that are free to move anddeformation of bodies that are not free to move. Force is expressed ingrams per unit area.

(j) "hydrophtlic" describes fibers or the surfaces of fibers which arewetted by the aqueous liquids in contact with the fibers. The degree ofwetting of the materials can, in turn, be described in terms of thecontact angles and the surface tensions of the liquids and materialsinvolved. Equipment and techniques suitable for measuring thewettability of particular fiber materials or blends of fiber materialscan be provided by a Cahn SFA-222 Surface Force Analyzer System, or asubstantially equivalent system. When measured with this system, fibershaving contact angles less than 90° are designated "wettable" orhydrophilic, while fibers having contact angles greater than 90° aredesignated "nonwettable" or hydrophobic.

(k) "integral" is used to refer to various portions of a single unitaryelement rather than separate structures bonded to or placed with orplaced near one another.

(l) "inward" and "outward" refer to positions relative to the center ofan absorbent garment, and particularly transversely and/orlongitudinally closer to or away from the longitudinal and transversecenter of the absorbent garment.

(m) "layer" when used in the singular can have the dual meaning of asingle element or a plurality of elements.

(n) "liquid impermeable" when used to describe a layer or laminate meansthat liquid such as urine will not pass through the layer or laminateunder ordinary use conditions in a direction generally perpendicular tothe plane of the layer or laminate at the point of liquid contact.

(o) "member" when used in the singular can have the dual meaning of asingle element or a plurality of elements.

(p) "nonwoven web" means a web of material which is formed without theaid of a textile weaving or knitting process.

(q) "operatively joined" and "operatively connected," with reference tothe attachment of an elastic member to another element, means that theelastic member when attached to or connected to the element, or treatedwith heat or chemicals, by stretching, or the like, gives the elementelastic properties; and with reference to the attachment of anon-elastic member to another element, means that the member and elementcan be attached in any suitable manner that permits or allows them toperform the intended or described function of the joinder. The joining,attaching, connecting or the like can be either directly, such asjoining either member directly to an element, or can be indirectly bymeans of another member disposed between the first member and the firstelement.

(r) "releasably attached," "releasably bonded," "releasably engaged" andvariations thereof refer to two elements being connected or connectablesuch that the elements tend to remain connected absent a separationforce applied to one or both of the elements, and the elements beingcapable of separation without substantial permanent deformation orrupture. The required separation force is typically beyond thatencountered while wearing the absorbent garment.

(s) "rupture" means the breaking or tearing apart of a material; intensile testing, the term refers to the total separation of a materialinto two parts either all at once or in stages, or the development of ahole in some materials.

(t) "stretch bonded" refers to an elastic member being bonded to anothermember while the elastic member is extended at least about 25 percent ofits relaxed length. Desirably, the term "stretch bonded" refers to thesituation wherein the elastic member is extended at least about 100percent, and more desirably at least about 300 percent, of its relaxedlength when it is bonded to the other member.

(u) "stretch bonded laminate" refers to composite material having atleast two layers in which one layer is a gatherable layer and the otherlayer is an elastic layer. The layers are joined together when theelastic layer is in an extended condition so that upon relaxing thelayers, the gatherable layer is gathered.

These terms may be defined with additional language in the remainingportion of the specification.

DETAILED DESCRIPTION OF THE EMBODIMENTS

With reference to FIGS. 1-4, an absorbent article formed according tothe invention is shown for purposes of illustration as a disposableundergarment 20 for adult incontinence. The invention may also beembodied in other types of garments, such as other disposable absorbentarticles, reusable absorbent articles, underwear, bathing suits,athletic supporters, prosthetics, or other personal care or health caregarments, or the like.

In general, the undergarment 20 includes first fasteners 52 that areeach bonded securely to a substrate 40 by an adhesive substance 80. Theadhesive substance 80 has a first zone 81 with a first basis weightgreater than zero and a second zone 82 with a second basis weightgreater than the first basis weight. The adhesive substance 80 in thefirst zone 81 assists in bonding the first fastener 52 to the substrate40 without bleeding through to the engagement surface 62 of the firstfastener. The adhesive substance 80 in the second zone 82 may besufficient to penetrate through to the engagement surface 62 of thefirst fastener 52, however, the area and positioning of the second zoneare controlled so that an ample region of the engagement surface isavailable to receive a complementary fastener 54.

The illustrated undergarment 20 defines longitudinal and transverseaxes, represented by arrows 22 and 24 in FIG. 2. The undergarment 20 hasopposite, front and back longitudinal end edges 26 and 27, andlongitudinal side edges 28 that extend between the longitudinal endedges. The undergarment 20 includes a first or front waist region 30, asecond or back waist region 32, and an intermediate, crotch region 34positioned between and interconnecting the front and back waist regions.The outer edges of the undergarment 20 define a periphery 36 in whichthe longitudinally extending side margins are designated 38 and thelaterally extending end margins are designated 3g. The end edges 26 and27 and side edges 28 are shown as generally straight, but optionally,may be curvilinear and contoured.

The front waist region 30 is contiguous with the front end edge 26 andextends longitudinally inward therefrom toward the transverse centerline of the undergarment 20. The back waist region 32 is contiguous withthe back end edge 27 and extends longitudinally inward therefrom towardthe transverse center line. The waist regions 30 and 32 comprise thoseupper portions of undergarment 20 which, when worn, wholly or partiallycover or encircle the waist or mid-lower torso of the wearer. Theintermediate, crotch region 34 comprises that portion of undergarment 20which, when worn, is positioned between the legs of the wearer andcovers the lower torso of the wearer. Thus, the crotch region 34 is thearea where insults of urine typically occur in the undergarment or otherdisposable absorbent article.

The undergarment 20 includes a substantially liquid impermeable moisturebarrier 40, an absorbent assembly 42 (FIG. 2) disposed on the moisturebarrier, and a substantially liquid permeable bodyside liner 44 bondedto the moisture barrier to sandwich the absorbent assembly therebetween.The moisture barrier 40 and bodyside liner 44 are desirably longer andwider than the absorbent assembly 42 so that the peripheries of themoisture barrier and bodyside liner may be bonded together usingultrasonic bonds, thermal bonds, adhesives, or other suitable means. Theperipheries of the moisture barrier 40 and the bodyside liner 44typically form the side and end margins 38 and 39 of the undergarment20. The absorbent assembly 42 may be bonded directly to the moisturebarrier 40 and/or the bodyside liner 44 using ultrasonic bonds, thermalbonds, adhesives, or other suitable means.

The moisture barrier 40 desirably comprises a material that is formed ortreated to be liquid impermeable. Alternatively, the moisture barrier 40may comprise a liquid permeable material and other suitable means (notshown), such as a liquid impermeable layer associated with the absorbentassembly 42, may be provided to impede liquid movement away from theabsorbent assembly. The moisture barrier 40 may also be gas permeable,such that gases encountered during use of the absorbent garment are ableto pass through the material under ordinary use conditions, over eitherall or part of its surface area.

The moisture barrier 40 may comprise a single layer of material or alaminate of two or mere separate layers of material. Suitable moisturebarrier materials include films, wovens, nonwovens, laminates of films,wovens, and/or nonwovens, or the like. For example, the moisture barrier40 may comprise a thin, substantially liquid impermeable web or sheet ofplastic film such as polyethylene, polypropylene, polyvinyl chloride orsimilar material. The moisture barrier material may be transparent oropaque and have an embossed or matte surface. One particular materialfor the moisture barrier 40 is a polyethylene film that has a nominalthickness of about 0.025 millimeter and a systematic matte embossedpattern, and that has been corona treated on both sides. Anothersuitable moisture barrier material is an adhesive or thermal laminatecomprising a cast or blown film formed of polypropylene, polyethylene orthe like, and a spunbond web formed of polypropylene and polyethylenemedium-crimped bicomponent fibers in a 50/50 side-by-side configuration.

The absorbent assembly 42 comprises materials adapted to absorb andretain liquid waste. The absorbent assembly 42 may comprise variousabsorbent materials, such as an air-formed batt of cellulosic fibers(i.e., wood pulp fluff) or a coform material composed of a mixture ofcellulosic fibers and synthetic polymer fibers. Polymer fibers may beincorporated, for example, in the manner described in U.S. Pat. No.5,227,107 issued Jul. 13, 1993, to Dickenson et al. The absorbentassembly 42 may also include compounds to increase its absorbency, suchas 0-95 weight percent of organic or inorganic high-absorbencymaterials, which are typically capable of absorbing at least about 15and desirably more than 25 times their weight in water. Suitablehigh-absorbency materials are described in U.S. Pat. Nos. 4,699,823issued Oct. 13, 1987, to Kellenberger et al. and 5,141,343 issued Sep.15, 1992, to Kellenberger, which are incorporated herein by reference.High-absorbency materials are available from various commercial vendors,such as Dow Chemical Company, Hoechst Celanese Corporation, and AlliedColloids, Inc. The absorbent assembly 42 may also include tissue layersor acquisition or distribution layers to help maintain the integrity offibrous absorbents or transport liquids (not shown).

The bodyside liner 44 is formed of a liquid permeable material so thatliquid waste, and possibly semi-solid waste as well, can pass throughthe liner and be absorbed by the absorbent assembly 42. Suitablebodyside liners 44 may comprise a nonwoven web or sheet of wet strengthtissue paper, a spunbonded, meltblown or bonded-carded web composed ofsynthetic polymer filaments or fibers, such as polypropylene,polyethylene, polyesters or the like, or a web of natural polymerfilaments or fibers such as rayon or cotton. In addition, the bodysideliner 44 is desirably nonelastic and may be treated with a surfactant toaid in liquid transfer. In a particular embodiment of the invention, theliner 44 comprises a nonwoven, spunbond polypropylene fabric composed ofabout 2.8-3.2 denier fibers formed into a web having a basis weight ofabout 22 gsm and density of about 0.06 gm/cc. The fabric is surfacetreated with about 0.28 weight percent of a surfactant commerciallyavailable from Rohm and Haas Co. under the trade designation TritonX-102.

The undergarment 20, portions of which are in a stretched and laid flatcondition in FIG. 2, is illustrated as having a rectangular periphery36. Of course, the undergarment 20 may optionally be hourglass-shaped,I-shaped, T-shaped, or irregularly-shaped. The general shape of theabsorbent assembly 42 may correspond to the shape of the undergarment 20or assume a different shape.

Desirably although not necessarily, the undergarment 20 also includesleg elastic members 46 to draw and hold the side margins 38 of theundergarment 20 against the legs of the wearer and form a sealtherewith. The elongated leg elastic members 46 are longitudinallyorientated in each side margin 38, extending toward the front and backend edges 26 and 27. The leg elastic members 46 are positioned in theillustrated embodiment between the moisture barrier 40 and the bodysideliner 44. Using ultrasonic bonds, adhesives, thermal bonds, or othersuitable means, the leg elastic members 46 are attached in a stretchedcondition to the moisture barrier 40, the bodyside liner 44, or both, ineither a straight or a curved shape. Alternatively, the leg elasticmembers 46 may be attached in a relaxed state to a gathered portion ofthe moisture barrier 40, the bodyside liner 44, or both.

The leg elastic members 46 may be formed of a dry-spun coalescedmultifilament elastomeric thread sold under the tradename LYCRA andavailable from E.I. Du Pont de Nemours and Company. Alternately, theelastic members may be formed of other typical elastics utilized in theundergarment-making art, such as a thin ribbon of natural rubber, astretch bonded laminate material comprising a prestretched elasticmeltblown inner layer sandwiched between and bonded to a pair ofspunbond polypropylene nonwoven webs, or the like. Elasticity could alsobe imparted to the absorbent article by extruding a hot melt elastomericadhesive between the moisture barrier 40 and the liner 44. Othersuitable elastic gathering means are disclosed in U.S. Pat. Nos.4,938,754 to Mesek and 4,388,075 to Mesek et al.

The attachment system in the illustrated embodiment includes a pair ofstrap members 50 and fastening components to releasably attach the strapmembers to the front and back waist regions 30 and 32. The fasteningcomponents have complementary fasteners 52 and 54 with surfaces that areadapted to repeatedly, releasably engage one another. The fasteners 52and 54 are adapted to resist disengagement in a shear mode yet easilyrelease from one another in a peel mode. This releasable engagement isaccomplished mechanically rather than adhesively. Suitable fastenersinclude self-engaging geometric shaped materials such as hooks, loops,bulbs, mushrooms, arrowheads, balls on stems, or the like.

The fastening components of the illustrated undergarment 20 include fourfirst fasteners 52 bonded to the moisture barrier 40 and four secondfasteners 54 bonded to the strap members 50. In the illustratedembodiment, the first fasteners 52 are formed of a loop material andwill also be referred to as loop fasteners 52, and the second fasteners54 are formed of a hook material and will also be referred to as hookfasteners 54. These fasteners 52 and 54 comprise the complementarycomponents of a hook-and-loop fastening system. It should be appreciatedthat the location of the hook-and-loop fasteners can be reversed, orthat other suitable mechanical fasteners can be substituted for thehook-and-loop fasteners.

The term loop material is intended to mean any fabric having a baseportion and a plurality of loop members extending upwardly from at leastone surface of the base portion. An illustrative loop material 60 isrepresentatively shown in FIG. 5. The loop material 60 is a flexiblefabric material having opposite major surfaces designated first majorsurface 61 and second major surface 62. The loop material 60 comprisesyarns 64 that are arranged to provide a raised loop construction inwhich the fabric is stabilized so that loops 66 are erect from the base68 of the fabric.

The loop material 60 may be formed of any suitable material, such asacrylic, nylon or polyester, and may be formed by methods such as warpknitting, stitch bonding or needle punching. The loop material 60 can bestabilized through napping, thermosetting or the like so that theindividual loops 66 are erect from the fabric base 68. The loopfasteners 52 can also be any suitable material having non-woven loopsthereon. The loop material 60 may optionally include a sizing (notshown), such as a vinyl acetate copolymer sizing available from NationalStarch and Chemical Corp. under the trade designation RESYN 5904,applied by mist deposition or other suitable means to the base 68 to afinal concentration of less than about 4 weight percent.

In a preferred embodiment, the loop fasteners 52 are formed of a loopmaterial 60 having a two bar warp knit construction, with from 21 to 41courses per inch (ca. 8-16 per cm.) and from 26 to 46 wales per inch(ca. 10-18 per cm.), of polyester yarn. In particular, about 15-35percent of the yarns may be composed of yarn having about 1-30individual filaments therein and having a yarn denier within the rangeof about 15-30 d (denier). In addition, about 65-85 percent of the yarnsmay be composed of yarn having about 1-30 individual filaments thereinand having a yarn denier within the range of about 20-55 d. Also, theloops may particularly be formed with a loop height from about 2 toabout 2.5 millimeters. The loop caliper may be from about 0.010 to about0.040 inch (ca. 0.25-1 mm.) and the basis weight may be from about 1.0to about 3.0 ounces per square yard (ca. 34-102 grams per square meter).One particular loop material 60 which has been found suitable for theloop fasteners 52 is identified as No. 19902 and is available fromGuilford Mills of Greensboro, N.C.

With additional reference to enlarged FIGS. 3 and 4, the loop fasteners52 are bonded to the surface of the moisture barrier 40 that is remotefrom the bodyside liner 44. Each of the loop fasteners 52 has oppositeside edges 70 and opposite end edges 72. The terms side edges and endedges are most adaptable to rectangular or nearly rectangular loopfasteners 52 where there is a distinct long dimension. Where the loopfasteners 52 are square, oval, curved or otherwise nonrectangularlyshaped, the distinction between side edges 70 and end edges 72 becomessomewhat arbitrary and is less significant.

Each of the loop fasteners 52 has a medial region 74 centrally locatedbetween the side and end edges 70 and 72. The medial region 74represents the principal engagement area for the fastener and generallyconstitutes from about 40 to about 98 percent of the surface area of theloop fastener 52. Each of the loop fasteners 52 also has peripheralportions 76 that are contiguous with the side and edge edges 70 and 72and extend inward therefrom to the medial region 74. The peripheralportions 76 represent outer areas of the loop fasteners 52 which are, inthe present invention, more securely bonded to the underlying substratethan the medial region 74. The peripheral portions 76 generallyconstitute from about 2 to about 60 percent of the surface area of theloop fastener 52, and particularly less than about 30 percent of thesurface area.

The loop fasteners 52 in each waist region 30 and 32 are desirablyseparated from one another and positioned adjacent the opposite sidesedges 28. Desirably although not necessarily, the loop fasteners 52 arealso spaced from the front and back end edges 26 and 27 and the sideedges 28 by at least about 0.25 inch (ca. 6.5 mm.). Alternatively, theremay be a greater number or a lesser number of loop fasteners 52 bondedto the moisture barrier 40 (not shown).

The loop fasteners 52 in the front and back waist regions 30 and 32 maybe the same size and be symmetrically positioned. More desirably,however, it has been determined that the particular loop fasteners 52disclosed herein provide adjustability for the attachment system and atthe same time promote the proper orientation of the undergarment 20 onthe wearer. In particular, the loop fasteners 52 are desirably attachedat specified angles in relation to the longitudinal and transverse axes22 and 24 of the undergarment 20 in order to promote a properorientation of the garment on the wearer.

The loop fasteners 52 in the front waist region 30 are desirablyrectangular in shape measuring approximately 1.25 inches by 3.38 inches(ca. 3 by 9 cm.). Each loop fastener 52 in the front waist region 30 isbonded to the moisture barrier 40 such that the longitudinal axis of thefastener is directed generally toward the nearest corner of theundergarment 20 and forms an angle in the range of from about 25 toabout 45 degrees with the transverse axis 24. The term longitudinal axisin reference to the fastener 52 is used to mean the axis parallel to thelonger dimension of the fastener.

Each loop fastener 52 in the back waist region 32 is desirably at least1 inch by 1 inch (ca. 25 by 25 mm.), providing a surface area of atleast about 1 in² (ca. 6.25 cm²). For example, the loop fasteners 52 inthe back waist region 32 may be rectangular and measure 1.5 inch by 2.0inch (38 by 51 mm.), with the longer dimension of the fastener alignedwith the transverse axis 24 of the undergarment 20. Alternately, theloop fasteners 52 in the back waist region 32 could be formed as asingle pad of loop material (not shown) attached across the back waistregion 32.

The loop tip orientation of the loop fasteners 52 has been found toaffect performance of the attachment system. The preferred loop material60 will have a loop tip orientation (not shown) in a single direction.As used herein, loop tip orientation refers to the general direction inwhich the tips of the loop members 66 are bent. This direction, whichwill be in the plane of the loop material, is caused by the nappingprocess used to make the loop material. However, the loop tiporientation may be generated by other processes as well, such asbrushing, scraping, nipping, rolling, pressing, differential crepeing,combing and so forth. The loop tip orientation of a loop material can beestablished by selecting appropriate manufacturing processes andequipment as known in the art.

Desirably, the loop tip orientation of either loop fastener 52 in thefront waist region 30 is generally perpendicular to the longitudinalaxis of the fastener and directed toward the front end edge 26 of theundergarment 20. Furthermore, the loop tip orientation of either loopfastener 52 in the back waist region 32 is desirably generally parallelto the longitudinal axis 22 of the undergarment 20 and directed towardthe opposite or front end edge 26 of the undergarment. Alternately,however, the loop tip orientation of either loop fastener 52 in the backwaist region 32 could be generally parallel to the transverse axis 24 ofthe undergarment 20 and directed toward the other loop fastener 52 inthe back waist region. Further arrangements of the loop fasteners aredisclosed in U.S. Pat. No. 5,386,595 issued Feb. 1, 1995, to D. Kuen etal. which is incorporated herein by reference.

As representatively illustrated in FIGS. 3 and 4, the loop fasteners 52are bonded to the moisture barrier substrate 40 with an adhesivesubstance 80. The adhesive substance 80 is disposed between the firstmajor surface 61 of the loop fastener 52 and the moisture barriersubstrate 40 and is effective to bond those surfaces together. Theadhesive substance 80 may comprise any suitable adhesive such as a hotmelt, or the like. By way of illustration, the adhesive substance 80 maycomprise a styrene-isoprene-styrene rubber block copolymer basedadhesive containing a rosin ester tackifying resin. One suitableadhesive is available from Findley Adhesives, Inc. of Wauwatosa, Wis.,U.S.A., under the trade designation H2122.

The adhesive substance 80 includes a first zone 81 and at least onesecond zone 82, which represent portions having different basis weightsof adhesive. The first and second zones 81 and 82 desirably comprisedifferent regions of an integral mass of adhesive 80. Alternatively, thefirst and second zones 81 and 82 may comprise separate masses ofadhesive 80 that are placed with or placed near one another. The firstand second zones 81 and 82 desirably abut one another. As a furtheralternative, however, there may be a transition zone (not shown) havingan intermediate basis weight or a gap (not shown) having no basis weightbetween the first and second zones 81 and 82. The basis weight ofadhesive 80 in either the first zone 81 or the second zone 82 can bedetermined according to the Basis Weight Test as sec forth in the TESTPROCEDURES section below.

The first zone 81 has a basis weight which will be referred to as afirst basis weight, and the second zone 82 has a basis weight which willbe referred to as a second basis weight. The first basis weight isgreater than zero so that the first zone 81 comprises a level ofadhesive that functions to bond, albeit relatively lightly, thecorresponding portions of the loop fastener 52 and the substrate 40. Theparticular basis weight of adhesive selected for the first zone 81 willdepend upon various factors, such as the type of adhesive, the projecteduse of the fastener, the type of loop material, the thickness of thefastener, and similar considerations. The first basis weight should beselected so that the adhesive substance 80 does not bleed through fromthe first zone 81 to the loops 66 of the first fastener 52. The firstbasis weight may, for purposes of illustration, be from about 0.003 toabout 0.01 grams per square centimeter (g/cm²), such as about 0.004g/cm².

By comparison, the second basis weight is at least about 1.5 timesgreater than the first basis weight. More desirably, the second zone 82has a second basis weight that is at least about 2 times greater, andmore particularly from about 4 to about 20 times greater, than the firstbasis weight for improved performance. While again recognizing that thebasis weight of adhesive 80 selected for the second zone 82 will dependupon various factors, it may be stated for purposes of illustration thatthe adhesive substance 80 in the second zone 82 may have a basis weightof about 0.019 g/cm².

The increased basis weight of adhesive 80 in the second zone 82 ascompared to the first zone 81 functions to more securely bond thoseportions of the loop fastener 52 and the substrate 40 that correspond tothe second zone. In fact, the adhesive 80 in the second zone 82 may evenbleed through the base 68 (FIG. 5) of the loop material 60 andeffectively deaden some of the loops 66 so they are not effective toengage the hook fasteners 54. The overall performance of the loopfastener 52 is enhanced as a result of the secure attachment afforded bythe higher basis weight of the second zone 82. Despite the possiblebleed through of adhesive 80 from the second zone 82, performance can beenhanced because the second zone 82 desirably covers much less area thanthe first zone 81. The surface area covered by the first zone 81 may beas little as about 60 percent of the surface area covered by the secondzone 82, but more particularly the surface area of the first zone 81 isgreater than the surface area covered by the second zone 82, anddesirably is at least about six times greater for improved performance.The larger surface area of the first zone 81 ensures that an adequatenumber of loops 66 will not be deadened and will be available toreleasably secure the hook fastener 54.

To enhance securement of the loop fasteners 52 to the moisture barriersubstrate 40 while maintaining adequate shear resistance between theloop and hook fasteners, 52 and 54, the adhesive substance 80 isdesirably applied so that the location of the first zone 81 correspondsto the medial region 74 of the loop fastener. Correspondingly, theadhesive substance 80 is applied so that the location of the secondzones 82 correspond to the peripheral portions 76 of the loop fastener52. As a result, even if the loop material 60 is relatively porous andthe added amount of adhesive 80 in the second zones 82 bleed through theloop material, only the loops 66 in the peripheral portions 76 of thefastener 52 will be deadened. The lower level of adhesive 80 in thefirst zone 81 should not bleed through the medial region 74 and thus theloops 66 in the medial region will be available for engagement with thehook fasteners 54.

The second zone 82 may form a continuous zone of relatively high basisweight adhesive that circumscribes the medial portion 74. Alternatively,one or a plurality of second zones 82 may bond a loop fastener 52 to themoisture barrier substrate 40. In the illustrated embodiment, the loopfasteners 52 in the front and back waist region 30 and 32 are bonded tothe moisture barrier substrate 40 with two second zones 82 of adhesive80 that are oriented along the end edges 72 of the loop fasteners 52(FIGS. 3 and 4). Desirably, the second zones 82 are located within about3 cm of the side or end edges 70 and 72 of the loop fasteners 52, andmore particularly within about 0.5 cm for improved performance.Alternatively, the loop fasteners 52 could be bonded to the moisturebarrier substrate 40 with two second zones 82 of adhesive 80 orientedalong the sides edges 70 of the loop fasteners 52 (not shown).

An apparatus 100 for bonding the loop fasteners 52 to the moisturebarrier 40 is representatively illustrated in FIGS. 6 and 7. Acontinuous web of loop material 60 is routed to the apparatus 100 andcut into discrete loop fasteners 52 which are then adhesively bonded toa continuous web of substrate material 40 at spaced locations. Theapparatus 100 can also process multiple webs of loop materialsimultaneously (not shown), and similar equipment may be used to applythe other loop fasteners 52 to the undergarment 20.

The continuous web of loop material 60 is supplied from a supply roll orother source (not shown) and routed in the direction of the arrows shownin FIG. 6. The web of loop material 60 passes over a guide roll 102 andbetween an adhesive die head 104 and a support roll 106. The die head104 is operated to apply the adhesive substance 80 (not shown in FIGS. 6and 7) onto the first major surface 61 of the web of loop material 60.In one particular embodiment, the temperature range of the adhesive is315° to 325° F. (157.2° to 162.8° C.) and the dwell time of the adhesiveis 7.75 to 7.89 seconds.

The die head 104 includes a slotted shim 108 which is separately shownin FIG. 7. The shim 108 includes a central, primary application region110 having a depth dimension representatively shown by reference numeral112. The shim 108 also includes a pair of supplemental applicationregions 114 which flank the primary application region 110. Thesupplemental application regions 114 each have a depth dimensionrepresentatively shown by reference numeral 116. Operation of the diehead 104 causes the adhesive substance 80 to flow over the primary andsupplemental application regions 110 and 114 of the shim 108 and ontothe web of loop material 60. The differing depth dimensions of theprimary and supplemental application regions 110 and 114 function toform the first zone 81 and the second zones 82 having different basisweights. The width of the supplemental application regions 114 isdesirably large enough for the adhesive to be able to readily enter thesupplemental application regions to the full depth dimension.

In particular embodiments, the supplemental application regions 114 mayhave a depth dimension 116 that is at least about twice as great as thedepth dimension 112 of the primary application region 110. For purposesof illustration, the depth 112 of the primary application region 110 maybe about 0.25 mm (0.01 inch) and the depth 116 of the supplementalapplication regions 114 may be about 5 mm (0.02 inch). The distancebetween the supplemental application regions 114 is desirably controlledso that the second zones 82 are positioned in the peripheral portions 76of the loop fasteners 52. With further reference to FIG. 7, the shim 108may optionally include a plurality of spaced-apart nubs 118 whichfunction to maintain adhesive flow through the primary applicationregion 110 of the shim 108.

The web of loop material 60 is thereafter routed over a guide roll 120and to a revolving roll 122. The revolving roll 122 is similar to thatdisclosed in U.S. Pat. No. 4,608,115 issued Aug. 26, 1986, to Schroth etal., which is incorporated herein by reference. The revolving roll 122is rotatably mounted on a frame (not shown) and rotates in the directionof the arrow shown in FIG. 6. The revolving roll 122 includes aplurality of rotatable platens 124 for receiving the web of loopmaterial 60, carrying discrete loop fasteners 52, and transferring theloop fasteners to the substrate material 40. The platens 124 arerotatable about axes that are desirably perpendicular to the axis of therevolving roll 122. Each platen 124 is directly mounted on a vacuumplate 126. The platens 124 can slidably rotate on the surface of thevacuum plates 126 while applying vacuum pressure to the loop material60.

The revolving roll 122 also includes a plurality of slip plates 128positioned at equal distances about the circumference of the revolvingroll. One slip plate 128 is located between each adjacent pair of vacuumplates 126. As the web of loop material 60 engages the revolving roll122, the web slides over a slip plate 128 and onto a platen 124.

A cutting roll 130 is rotatably mounted adjacent the revolving roll 122.The cutting roll 130 includes a cutting blade 132 that is rotated in thedirection of the arrow shown in FIG. 6 to engage the web of loopmaterial 60 on the platens 124. Discrete loop fasteners 52 are thussevered on the platens 124 from the web of loop material 60. The platens124 then carry the loop fasteners 52 from the cutting roll 130 to thesubstrate 40 at the location of an applicator roll 134. The cut loopfasteners 52 are maintained on the platens 124 from the cutting roll 130to the applicator roll 134 by operation of the vacuum plates 126. Theplatens 124 can be rotated at this stage to change the angle at whichthe loop fasteners 52 are applied to the substrate 40.

The applicator roll 134 is rotatably mounted adjacent the revolving roll122 so as to rotate in the direction of the arrow shown in FIG. 6. Theapplicator roll 134 includes striking members 136 comprising resilientmaterial such as rubber. The striking members 136 are alternatelyrotated into engagement with the substrate 40 to press the substrateagainst the platens 124. Because the loop fasteners 52 have the adhesivesubstance 80 applied on their sides facing outward of the revolving roll122 and toward the substrate 40, the compression of the substrateagainst the platen 124 will cause the loop fasteners to transfer fromthe platens and adhere to the substrate.

The strap members 50 (FIG. 1) are each generally rectangular strips ofmaterial having opposite forward and rearward end portions 85 and 86.The strap members 50 are preferably formed of an elastic material, whichis capable of stretching to approximately 2.8 to 3 times its relaxedlength. The strap members 50 preferably have a length from about 6inches to about 16 inches (ca. 15-41 cm.), and a width from about 0.5inch to about 2 inches (ca. 1-5 cm.). For example, each strap member 50may be 11 inches (ca. 28 cm.) long and 1 inch (ca. 2.5 cm.) wide. Thecut ends of the strap members 50 may be bonded by ultrasonics, adhesivesor other suitable means to prevent raveling.

The hook fasteners 54 are attached at each end portion 85 and 86 of eachstrap member 50, on the same side of the strap member. The hookfasteners 54 desirably comprise a single-sided hook material and formthe hook component of the hook-and-loop attachment system. The hookfasteners 54 may be of a variety of shapes, such as rectangular andmeasuring about 0.875 inch by about 1.125 inches (ca. 2.2 by 2.9 cm.).Each hook fastener 54 is attached to a strap member 50 by ultrasonicbonds, adhesives, stitches or other suitable means. As illustrated inFIG. 1, each hook fastener 54 may include a free end 88 that is roundedand void of hooks. The free end 88 provides a convenient surface forgrasping the hook fastener 54 to remove it from engagement with the loopmaterial 60. The hook fasteners 54 may be positioned in fullface-to-face contact with the strap members 50 (not shown), orpositioned such that hook fasteners extend past the ends of the strapmembers (FIG. 1).

Suitable hook material may be molded or extruded of nylon, polypropyleneor another suitable material. Desirable stiffness levels of the hookmaterial may be obtained from polymeric materials having a flexuralmodulus of about 70,000-120,000 pounds per square inch (ca. 4.83×10⁸-8.27×10⁸ nt/m²) and a Shore hardness value within the range of aboutD-40 to D-80, such as D-61. The hook fasteners 54 desirably containuni-directional hooks, with the machine direction of the hooks alignedwith longitudinal axis of the strap member 50, and the hooks directedtoward the opposite end portion 85 or 86 of the strap member. Onesuitable single-sided hook material for the hook fasteners 54 isavailable from Velcro Industries B.V., Amsterdam, Netherlands oraffiliates thereof, and is identified as HTH-840 with No. 22uni-directional hook pattern.

The shape, density and polymer composition of the hooks may be selectedto obtain the desired peel and shear force resistance values, ashereinafter described, between the hook fasteners 54 and the loopfasteners 52. One skilled in the art would recognize, for instance, thata mere aggressive hook material may comprise a material with a greateraverage hook height, a greater percentage of directionally-alignedhooks, or a more aggressive hook shape. As one example, the density ofthe hook members may be more than 50 hooks per square inch (ca. 8 persquare cm.), and mere particularly within the range of about 440 toabout 1040 hooks per square inch (ca. 68-161 per square cm.), such asabout 740 hooks per square inch (ca. 115 per square cm.). The rowdensity may be within the range of about 20 to about 60 rows per linearinch of width (ca. 8-24 per linear cm.), such as about 40 rows perlinear inch of width (ca. 16 per linear cm.). The hook members may behook-shaped, mushroom-shaped, arrow-shaped or any other desired shape.

In use, the undergarment 20 is positioned on the body of the wearer andsecured in position using the attachment system. The wearer can engageone hook fastener 54 of each strap member 50 with one of the loopfasteners 52 in the back waist region 32. After stretching or relaxingthe strap members 50 to obtain the desired tension therein, the wearercan then engage the opposite hook fasteners 54 of each strap member 50with one of the corresponding loop fasteners 52 in the front waistregion 30. The angled orientation of the loop fasteners 52 prompts thewearer to secure the hook fasteners 54 so that the strap members 50 arealigned with the longitudinal axis of the front loop fasteners 52,beneficially causing the strap members to be positioned toward the hipsof the wearer.

The adhesive substance 80 functions to securely bond the loop material60 to the moisture barrier substrate 40. The loop fastener 52 therebyresists delamination in response to shear forces generated by engagementwith the hook fastener 54. The increased basis weight of the second zone82 is largely but not entirely responsible for the secure bond of theloop material 60 to the substrate 40. Furthermore, the relatively smallarea of the second zone 82 and its application to the peripheralportions 76 means that relatively few loops 66 will be deadened as aresult of bleed through of adhesive 80 from the second zone. The medialregion 74 will be bonded to the substrate as well although the loops 66in the medial region will remain available for engagement with the hookfasteners 54.

An alternative undergarment 90 according to the present invention isillustrated in FIG. 8, where components similar to those previouslydescribed have the same reference numeral. The undergarment 90 includesa moisture barrier 92 comprising an inner liquid impermeable layer 94and an outer fibrous layer 96. In one particular embodiment, the innerlayer 94 comprises a cast or blown film formed of polypropylene,polyethylene or the like, and the outer layer 96 comprises a spunbondweb formed of polypropylene and polyethylene medium-crimped bicomponentfibers in a 50/50 side-by-side configuration. The inner and outer layers94 and 96 may be bonded together such as by a patterned application ofadhesive, by thermal bonds, or other suitable means. The adhesivesubstance 80 is bonded directly to the outer layer 96. As suggested byFIG. 8, the second zones 82 of the adhesive substance 80 tend to morethoroughly penetrate the fibers of the outer layer 96 to better securethe peripheral portions 76 of the loop fastener 52 to the moisturebarrier 92.

In general, the adhesive substance 80 having first and second zones 81and 82 with the above-reference properties may be used with a variety ofdisposable absorbent products. Examples of diaper configurations, forinstance, are disclosed in U.S. patent application Ser. No. 08/168,615by T. Roessler et al., filed Dec. 16, 1993, and titled "Dynamic FittingDiaper" (Attorney Docket No. 10,961); and U.S. patent application Ser.No. 08/168,615 by E. D. Johnson et al., filed Aug. 12, 1994, and titled"Diaper With Improved Lateral Elongation Characteristics" (AttorneyDocket No. 11,629). The adhesive substance 80 having first and secondzones 81 and 82 with the above-reference properties may, in fact, beused bond any type of flexible fabric such as a mechanical fastener to asubstrate.

The following EXAMPLES are provided to give a more detailedunderstanding of the invention. The particular amounts, proportions,compositions and parameters are meant to be exemplary, and are notintended to specifically limit the scope of the invention.

TEST EXAMPLE 1

A number of test undergarments having the general configuration of theundergarment 20 shown in FIG. 1 were constructed. In each testundergarment, one of the loop fasteners 52 from the back waist region 32was bonded to the moisture barrier using an adhesive substance 80 havingdesignated first and second zones 81 and 82. The remaining three loopfasteners 52 of the test undergarments were bonded to the moisturebarrier with the same adhesive substance 80 applied at a generallyconstant basis weight.

The test undergarment included a moisture barrier 92 as described inrelation to FIG. 8 which comprised an adhesive laminate of an innerlayer 94 and an outer layer 96. The inner layer 94 was formed of apolyethylene film having a basis weight of about 24 grams per squaremeter and a thickness of about 0.025 millimeter. The outer layer 96comprised a point bonded spunbond nonwoven formed of polypropylene andpolyethylene medium-crimped bicomponent fibers in a 50/50 side-by-sideconfiguration. The outer layer 96 had a basis weight of about 42.25grams per square meter.

The test undergarment also included an absorbent assembly 42 disposed onthe moisture barrier 92 and a bodyside liner 44 disposed on theabsorbent assembly. The bodyside liner 44 comprised a spunbondpolypropylene web. The absorbent assembly 42 was formed of cellulosefluff, sprayed polypropylene filaments, and superabsorbent particles.The absorbent assembly 42 was wrapped in tissue and attached to themoisture barrier 92 using a construction adhesive. The bodyside liner 44was positioned over the absorbent assembly 42 and bonded to the outerperiphery of the moisture barrier 92. The test undergarment also includeelastic leg members 46 secured along the two side margins 38 in thecrotch region 34 of the garment.

The fastening system for the test undergarment included the four loopfasteners, which were formed of a tricot warp knit, brushed (napped)polyester yarn fabric purchased from Guilford Mills (No. 33517). A vinylacetate copolymer sizing (RESYN 5904 from National Starch and ChemicalCorp.) had been mist deposited on the back face of the loop materialprior to heat treatment to obtain a final concentration of less than 4weight percent. The two loop fasteners 52 in the front waist region 30measured 1.25×3.37 inches and were positioned to form an angle of about33 degrees with the transverse axis. The two loop fasteners 52 in theback waist region 32 measured 1.5×2.0 inches and were aligned with thetransverse axis 24 of the garment.

The adhesive substance 80 used to attach the loop fasteners 52 to themoisture barrier substrate 92 comprised a styrene-isoprene-styrene blockcopolymer based adhesive with a rosin ester tackifying resin fromFindley Adhesives, Inc. One of the loop fasteners 52 in the back waistregion 32 was bonded to the moisture barrier 92 using a multiple levelslotted shim as shown in FIG. 7. The other three loop fasteners 52 werebonded to the moisture barrier 92 using a single level shim so that theadhesive substance 80 was applied at a generally constant basis Weight.

The two elastic strap members 50 were formed of an elastic materialpurchased from Shelby Elastics of Shelby, N.C., U.S.A. The strap members50 had a length of about 10.5 inches (26 cm.) and a width of about 1inch (2.5 cm.). The strap ends were ultrasonically bonded to preventraveling. The hook fasteners 54 that were bonded to each end of eachstrap member 50 were purchased from Velcro USA and identified as No.HTH-840 including 22 Series hooks. The hook fasteners 54 measured0.876×1.625 inches (2.23×4.13 cm) and had the unidirectional hookspointing toward the center of the strap. Each hook fastener 54 had threerows of hooks at a free end ultrasonically deformed to form finger tabs.The hook fasteners 54 were ultrasonically bonded to the strap members50.

Comparative Example 1

For purposes of comparison, comparative undergarments were alsoconstructed. All of the loop fasteners 52 in the comparativeundergarments were bonded to the moisture barrier substrate 92 using asingle level shim so that the adhesive substance 80 was applied at agenerally constant basis weight. In all other respects, the comparativeundergarments were the same as the test undergarments.

The test and comparative undergarments were both examined to determinethe distribution of the adhesive substance 80 in the finished product.The basis weight of the adhesive substance 80 was determined accordingto the Basis Weight Test as set forth in the TEST PROCEDURES sectionbelow. The loop fastener 52 on the test undergarment that had theadhesive 80 applied using the multiple level slotted shim was found tohave a first zone 81 measuring 3.0 by 3.8 cm for an area of 11.4 cm² andtwo second zones 82 each measuring 3.0 by 0.3 cm for a combined area of1.8 cm². On one of the test undergarments, the first zone 81 weighed0.0538 g for a basis weight of 0.00472 g/cm², and the second zones 82had a combined weight of 0.0350 g for an average basis weight of 0.0194g/cm². On a second test undergarment, the first zone 81 weighed 0.0532 gfor a basis weight of 0.00467 g/cm², and the second zones 82 had acombined weight of 0.0354 g for an average basis weight of 0.0197 g/cm².The comparably positioned loop fasteners 52 on the comparativeundergarments were found to have a single, generally uniformdistribution of adhesive. On one of the comparative undergarments, theadhesive measured 3 by 4.4 cm for an area of 13.2 cm², and weighed0.0897 g for a basis weight of 0.0068 g/cm². On a second comparativeundergarment, the adhesive measured 3 by 4.45 cm for an area of 13.35cm², and weighed 0.0889 g for a basis weight of 0.0067 g/cm².

The hook-and-loop fastening systems of both the test undergarments andthe comparative undergarments were also evaluated for their resistanceto shear forces. The fastening systems were evaluated according to theHook And Loop Shear Test as set forth in the TEST PROCEDURES sectionbelow. A comparison of the shear resistance of the loop fastener 52 ofthe test undergarment that was attached with the adhesive substance 80applied in zones 81 and 82 of different basis weight to the comparablypositioned loop fastener 52 of the comparative undergarment is set forthin Table 1. Three sets of 20 test undergarments and one set of 20comparative undergarments were tested.

                  TABLE 1                                                         ______________________________________                                        Hook And Loop Shear Test                                                      (reported in pounds)                                                          Specimen  Test Undergarment                                                                             Comparative                                         Number    Set 1  Set 2     Set 3                                                                              Undergarment                                  ______________________________________                                        1         11.75  11.75     14.15                                                                              10.00                                         2         11.60  12.75     13.30                                                                              8.70                                          3         13.45  12.05     12.95                                                                              9.70                                          4         12.50  12.45     12.40                                                                              10.20                                         5         13.10  12.50     14.00                                                                              10.00                                         6         12.80  12.90     14.15                                                                              9.90                                          7         13.00  13.55     14.80                                                                              9.75                                          8         12.30  13.25     12.05                                                                              10.05                                         9         12.90  13.70     12.85                                                                              9.85                                          10        13.15  14.10     13.00                                                                              11.05                                         11        12.50  12.50     12.85                                                                              10.50                                         12        13.65  12.55     13.45                                                                              10.65                                         13        13.15  12.80     14.65                                                                              9.80                                          14        12.25  13.50     11.25                                                                              9.50                                          15        12.80  12.60     13.85                                                                              9.80                                          16        13.35  12.60     12.30                                                                              9.45                                          17        13.55  12.50     11.70                                                                              9.70                                          18        12.95  13.50     13.75                                                                              10.05                                         19        13.45  12.60     13.60                                                                              10.10                                         20        13.45  12.35     12.40                                                                              10.40                                         Average   12.88  12.83     13.17                                                                              9.96                                          Stnd. Deviation                                                                         0.58   0.59      0.97 0.49                                          ______________________________________                                    

The three sets of test undergarments had shear resistance values of12.88 pounds (5.84 kg), 12.83 pounds (5.82 kg), and 13.17 pounds (5.97),The comparative undergarment had a significantly lower shear resistancevalue of 9.96 pounds (4.52 kg). For all shear resistance values recordedexcept one, the loop fastener separated from the substrate material. Theexception was the thirteenth specimen of set 3 of the test undergarment,where the hook fastener pulled away from the loop fastener.

TEST PROCEDURES

Basis Weight Test

This test has been designed to measure the basis weight of an adhesivesubstance which may be used in an absorbent article, such as adisposable absorbent undergarment. A portion of the product to be testedis cut from the product. The portion should measure at least about 6 by7 cm, with the longer dimension parallel to the transverse axis of theproduct and the shorter dimension parallel to the longitudinal axis ofthe product. The portion should include the entire fastener to betested, and can be made larger if necessary to include the entirefastener.

Place the portion on a smooth, stiff cardboard surface, oriented so thatthe longer dimension of the portion lies left to right. With a glassmicroscope slide as a straight edge oriented parallel with the longerdirection, trim off the top and bottom sections of the portion to leavea 3.0 cm middle section. Peel off any portions of the product such asthe moisture barrier that can be removed without loosing any adhesive.This resulting sample should measure 3 cm by the width of the fastenerand consist of the fastener, the adhesive, and some other fibers thatcould not be peeled from the sample. Note that the sample orientation orthe 3 cm dimension may need to be changed if this results in the removalof significant zones of adhesive.

Place the sample on a couple of thick pieces of poly film such as pageprotectors and place the combination on a light table. Examine thesample for relatively dark areas which represent thicker areas ofadhesive. With a fresh razor blade, bear down through the fastener andinto the poly film, immediately adjacent to the thicker areas ofadhesive. Cut the sample into specimens which appear to have commonthicknesses of adhesive. Measure the area of each specimen, includingonly areas actually covered by adhesive.

Weigh each specimen. Remove adhesive from each specimen by chloroform(CHCl₃) extraction at room temperature. Evaporate to dryness andre-weigh each specimen to determine the weight of adhesive that had beenpart of the specimen. The basis weight of the adhesive for a particularspecimen is the adhesive weight divided by the surface area.

Hook And Loop Shear Test

The Hook And Loop Shear Test measures the force needed to shear a loopfastener from the underlying substrate material or the force needed todisengage the hook fastener from the loop fastener, whichever failsfirst. In general, twenty specimens of loop or other first fasteners arecut from the product such as an undergarment to which they are attached.Then a hook or second fastener is applied to the designated loopfastener, engaged by applying pressure with a roll down, inserted intotensile testing jaws, and pulled until either the hook fastenerdisengages the loop fastener or the loop fastener delaminates from thesubstrate material. Pass or fail and the mode of separation aredocumented. The shear value for a particular configuration of fastenercomponent is the average of the twenty values obtained in the test.

The test employs the following equipment and materials:

1. Marker, permanent (e.g. Stanford Sharpie)

2. Paper cutter, for example a paper cutter identified as Jacques, Jr.from TMI, Amityville, N.Y. 11701.

3. Scissors

4. Roll down, 4.5 lb., hand held, such as one available fromChemsultants International, Mentor, Ohio, 44061-1118.

5. MecMesin End Seal Tester with a Chatilion DF150 Digital Gauge, 3-inchfabric grips and a fixed 12"/min. (300 mm/min) speed. The end sealtester employs a test stand identified as Model M1-000EL 200 lb.capacity with 1.6-31.5 in/min speed option, obtained from MecMesin Inc.,Santa Rosa, Calif. U.S.A. The gauge is identified as Model DFIS-50 forcegauge with 50 lb. cell, and the fabric grips are identified as ModelGF-7 fabric roller grips 3 inch wide. Both the gauge and grips can beobtained from Chatilion and Sons Inc., Greensboro, N.C. U.S.A.

6. Calibration weight(s) used to verify the accuracy of the ChatilionGauge; traceable to the National Institute of Standards and Technologyand within the range of values usually tested.

7. Hook strap comprising a hook fastener bonded to a strap formed ofelastic material. The strap is approximately 13 cm long and 2.5 cm wideand can be obtained from Shelby Elastics. The hook fastener is bonded toone end of the strap. The hook fastener measures 2.23 by 4.13 cm andincludes uni-directional hook material identified as HTH 840 No. 22available from Velcro Industries B.V., pointing in the direction of thestrap.

8. Ruler, millimeter increments

Proper training is essential for the proper execution of this procedure.The technician should also practice before attempting to do the test. Inparticular, it is important that the tester is properly trained on howto use the roller in order to maintain a constant weight. When using thehand held roll down hold the roller handle lightly at the end with thestorage support legs pointing up, and always keep the handle parallel tothe material being rolled. Lift up the roller handle slightly so thatthe pin is just touching the bottom of the pin hole. The weight appliedto the hook fastener should come only from the roller, not from thetechnician or the handle. When the rolldown is not in use, the handleshould be flipped over.

Samples products are collected and labeled. To avoid any damage to thehook or loop materials prior to testing, avoid excessive handling of theproduct/materials. The hook and loop material should not come intocontact with each other prior to testing. The specimens to be tested areprepared in the following manner.

1. Lay out the product with the loop fasteners facing up.

2. Using either a scissors or cutting board, cut the loop fastener outof the product, leaving 40 millimeters of the substrate material alongthe edge of the loop fastener toward the center of the product and 15millimeters of substrate material, if available, along all other edgesof the loop fastener. Remove any fluff from the specimens.

3. Carefully label each loop fastener so that the relative location ofthe loop fastener on the product is known.

4. Gently lay a hook strap on each of the loop fasteners so that thehook fastener is centered on the loop fastener and the strap ispositioned over the 40 mm section of the substrate material. Ifpossible, make sure there is 20 mm of loop material between the hookfastener and the end of the loop fastener that is remote from the 40 mmsection of substrate material. Note the hooks must be attached to theloop material.

5. Roll the hooks using the 4.5 lb. roller. Make 3 cycles over eachhook. One cycle is defined as one pass over the specimen then a secondpass in the opposite direction. When one cycle has been completed theroller will be at the starting point. Count 1 second in each direction.

The equipment is then set up in the following manner. Equipmentmanufacturers or their literature should be consulted for specificcalibration information.

1. Turn on the power to the Chatilion gage by switching the toggle tothe "ON" position.

2. Turn on the power to the base of the MecMesin Test Stand. Allow thegage to warm up for a minimum of 15 minutes.

3. On the gage, press the units button until the "lb" measurementappears in the digital display window. If metric units are desired,press UNITS button until "KG" appears in the display window.

4. Adjust the distance between the clamps to 2.5 inches (63.5 mm) bymoving the lower limit adjustment collar. Set the upper collar at adistance that allows the specimen to completely separate.

Each specimen is then tested according to the following procedure.

1. Insert the specimen so that it is centered in the jaw width and thehook side of the specimen is facing toward the tester. When closing theupper jaw, make sure the specimen is level and the loop fastener isbelow the jaw clamp. Only the 40 mm long tab of substrate material thatextends beyond the loop fastener should be clamped in the upper jaw.

2. Tuck the tab of substrate material behind the lower clamp andposition the strap in the lower jaw so the strap-to-hook fastener bondarea is just above the lower jaw. Center the strap. It is important thatthe hook/loop interface is centered and vertical between the jaws. If itis not straight, open the jaws and reclamp the specimen.

3. Press the ZERO on the Mecmesin control panel The gauge will read"00.00". This display is required for each specimen.

4. Begin the test by moving the control panel UP/DOWN switch to the UPposition. If the substrate material slips in the lower jaw, hold thelower jaw down against the specimen.

5. Upon complete separation of either the hook/loop or loop/substrate,return the upper jaw by moving the switch to the "Down" position.

6. Record the peak value that is displayed and the mode of failure.

The foregoing detailed description has been for the purpose ofillustration. Thus, a number of modifications and changes may be madewithout departing from the spirit and scope of the present invention.For instance, alternative or optional features described as part of oneembodiment can be used to yield another embodiment. Additionally, twonamed components could represent portions of the same structure.Therefore, the invention should not be limited by the specificembodiments described, but only by the claims.

We claim:
 1. A method of forming a fastening component, comprising thesteps of:providing a first fastener comprising a flexible fabric;providing substrate; and applying an adhesive substance between thefirst fastener and the substrate and bonding the adhesive substance toboth the first fastener and the substrate, the adhesive substancecomprising: a first zone having a first basis weight greater than zero;and a second zone having a second basis weight at least about 1.5 timesgreater than the first basis weight.
 2. The method of claim 1, whereinthe step of applying the adhesive substance comprises causing theadhesive substance to flow over a slotted shim having a primaryapplication region and at least one supplemental application region, thesupplemental application region having a depth dimension at least twiceas great as a depth dimension of the primary application region.
 3. Themethod of claim 1, wherein the second basis weight is at least about 2times greater than the first basis weight.
 4. The method of claim 3,wherein the second basis weight is from about 4 to about 20 timesgreater than the first basis weight.
 5. The method of claim 1, whereinthe first zone covers a first area, the second zone covers a secondarea, and the first area is at least about 6 times greater than thesecond area.
 6. The method of claim 1, wherein the first fastener has afirst major surface and a second major surface, and the second majorsurface comprises a plurality of loops adapted for releasable engagementwith a complementary fastener.
 7. The method of claim 1, wherein thesubstrate comprises an inner liquid impermeable layer and an outerfibrous layer, and the adhesive substance is bonded directly to theouter fibrous layer.
 8. A method of forming a fastening component,comprising the steps of:providing a first fastener comprising a flexiblefabric, the first fastener having a first major surface, a second majorsurface, a medial region, and peripheral portions surrounding the medialregion; providing a substrate; and applying an adhesive substancebetween the first major surface and the substrate and bonding theadhesive substance to both the first major surface and the substrate,the adhesive substance comprising:a first zone disposed on the medialregion and having a first basis weight greater than zero; and anabutting second zone disposed on the peripheral portions and having asecond basis weight at least about 1.5 times greater than the firstbasis weight.
 9. The method of claim 8, wherein the step of applying theadhesive substance comprises causing the adhesive substance to flow overa slotted shim having a primary application region and at least onesupplemental application region, the supplemental application regionhaving a depth dimension at least twice as great as a depth dimension ofthe primary application region.
 10. The method of claim 8, wherein thesecond basis weight is at least about 2 times greater than the firstbasis weight.
 11. The method of claim 10, wherein the second basisweight is from about 4 to about 20 times greater than the first basisweight.
 12. The method of claim 8, wherein the first zone covers a firstarea, the second zone covers a second area, and the first area is atleast about 6 times greater than the second area.
 13. The method ofclaim 8, wherein the second major surface comprises a plurality ofloops.
 14. The method of claim 8, wherein the medial region has asurface area of from about 40 to about 98 percent of a surface area ofthe first fastener.
 15. The method of claim 8, wherein the substratecomprises an inner liquid impermeable layer and an outer fibrous layer,and the adhesive substance is bonded directly to the outer fibrouslayer.